Pyrethrin and dialkoxyalkyl phthalate insecticide



Patented Oct. 28, '1947 )UNITED STATES, PATENT, 'QFFICE rrnn'rnnm ANDmALKoxYALKYL PHTHALATE msnc'ricmn 7 Howard A. Jones, Orlando, Fla., andRaymond C. Bushland, Fort Worth, Tex assignor to United States ofAmerica, as represented by the Secretary of Agriculture No Drawing.Original application'April 28, 1944, r I

Divided and this application September 19, 1944, Serial No. 554,865

' Claims. (01. revs-24) (Granted under the act of March a, 1883, as

Serial No. 533,267.

- 1 This application is March 3; 1883, as amended by the act of April30, 1928, and the invention herein described, if patented, may bemanufactured and used by or for the Govermnent of the United States ofAmerica for governmental purposes without the payment to us of anyroyalty thereon. r

This is a division of our copendin'g application for patent, Serial No.533,267, filed April 28, 1944. The present invention relates toinsecticidal compositions, and'more particularly to insecticidalcompositions containing pyrethrum. The principal object of thisinvention is to provide a new and improved insecticidal composition.

A further object is to enhance the effectiveness of pyrethrum bycombining with it an activator or synergist.

It has long been known that pyrethrum is an effective insecticide.Pyrethrum has certain disadvantages, however, among which are its costand the high concentrations needed to obtain complete kill of certainspecies of insects.

made under the act-oi amended April 30, 1928; 370 0. G.- 757) We havefound that when pyrethrum is com- I bined with dialkyl or substituted.dialkyl phthalates the resulting composition has an insecticidal valuefar greater than would be expected as a result of additive eflect of thecomponents. The high insecticidal eflicacy of the composition isespecially surprising in view, of the fact that the aforementionedphthalates possess very little insecticidal value in themselves. Thus,we have found that powders comprising a concentrated extract ofpyrethrum flowers, a. dialkyl or substituted dialkyl phthalate, and aninert carrier such as pyrophyllite are far more effective in killingbody lice (Pediculus humanus corporz's) than would be expected from theinsecticidal value of any of the components alone. There is a highdegree of. activation of the pyrethrins by these phthalates.

We have prepared powders by dissolving a given amount of pyrethrumextract containing percent pyrethrins and a. given amount of dialkyl orsubstituted dialkyl phthalate in amutual, volatile solvent, mixing thiswith the desired amount of pyrophyllite, and subsequently removin thevolatile solvent by evaporation. The resulting pow- 5 The concentrationsof pyrethrins shown above 2 are shown the insecticidal resultsobtainedin a series of tests with powders prepared andtested as described. Theresults are stated inv terms of percent surviving lice after 24 hoursexposure to the powdered insecticidal compositions.

1.0 percentphthalate 0.5 percent phthalate .Plus 0.01% Alone no Plus0.01% Alone no pyrethrins pyrethrins pyrethrins pyrethrins In controltests of this type without any insecticidal treatment, there is anaverage of about- 80' percent surviving or live lice after 24 hours.

(0.025 percent and 0.01 percent) when used alone gave the same averagepercent survival as the controls. Thus, this concentration of pyrethrinsis completely non-toxic' It will be noted from the above tables that ingeneral the'phthalates tested were at the most only very slightly toxic,even at the high concentration of 2 percent.

- :However, it will be seen from the table that in every case thecomposition .comprising a nontoxic concentration of pyrethrins with adialkyl ders were dusted on underwear-cloth sleeves, the

sleeves applied to the human arm, o leg, 25 recently fed, youngadultlice introduced, and the sleeves taped to the body. The lice weretherefore under essentially natural conditions. replicates of eachtreatment were made. Exami nations for living and dead lice were made 24hours after treatment. In Table I and Table II Several or substituteddialkyl phthalate possessed a definitely greater insecticidal value(lower percentage of surviving or liv lice) than the phthalate alone.For example, 2 percent-of dibutyl phthalate alone applied as describedleft 31 percent live lice in 24 hours. However, by combining this with aconcentration of pyrethrins which in itself has no insecticidal value, acomposition was ob tained that gave complete control of lice in24 hours.Similar results have been obtained from tests on men grossly infestedwith lice.

The aforementioned phthalatcs a r e cited merely as examples and it isnot to be inferred that other esters of phthalic acid added topyrethrins cannot be used. Further, the above examples are not to beconstrued as limiting either the methods of preparation and applicationof this novel insecticidal composition or the kinds of insects to whichit may be applied. The proportions of pyrethrum and phthalate may bevaried over a wide range. The composition may be used either as a dustor as a spray with or without solvent. It may also be used incombination with other insecticides.

Having thus described our invention, we claim:

1. An insecticidal composition comprising pyrethrum anddi-beta-methoxyethyl phthalate.

2. An insecticidal composition comprising pyrethrum anddi-beta-ethoxyethyl phthalate.

3. An insecticidal composition comprising pyrethrum anddi-beta-butoxyethyl phthalate.

4.. An insecticidal composition comprising py rethrum and a compoundselected from the class 4 I of di-beta-alkoxyethyi phthalates having thegeneral formula 1- COO CHzCHaOR CO 0 CHICHQOR C 00 CHaCHzO R COOCHaCHzORwhich R is a saturated alkyl group containing lfl'Ol'Ii 127 four carbonatoms HOWARD A. JONES. RATE/EDDIE C. BUS i

